Ashly FTX-1001, FTX-2001, FTX-1501, CFT-1800 User Manual

FTX-1001
FTX-1501
FTX-2001

CFT-1800

Power Amplifier

Series III

Operating Manual

ASHLY AUDIO INC.

847 Holt Road Webster, NY 14580-9103 Phone: [phone]

Toll-Free: [phone] Fax: [phone] Inter net: http://www.ashly.com/

Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

Table Of Contents

1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 UNPACKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3 AC POWER REQUIREMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.1 AC Voltage Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.2 Current Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.3 AC Grounding Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4 CABLE REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4.1 Input Cables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4.2 Output Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5 RACK-MOUNTING REQUIREMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5.1 Mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5.2 Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5.3 Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

6 FRONT PANEL FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6.1 Power Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6.2 Thermal Status Meters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6.3 Output Meters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6.4 Clipping Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6.5 Protect Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

7 REAR PANEL FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

7.1 Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

7.2 Normal/Bridging Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

7.3 Stereo/Parallel Mono Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

7.4 Level Controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

7.5 Speaker Outputs - Binding Posts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

8 INPUT OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8.1 Input Isolation Transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8.2 Peak Limiter Compressor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8.3 Two-Way Crossover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8.4 Mic-Line Mixer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

9 TYPICAL APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

9.1 Stereo Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

9.2 Parallel Mono Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

9.3 Bridged Mono Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

10 DESIGN THEORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1 1 TROUBLESHOOTING TIPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

11.1 No Audio Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

11.2 Distorted Sound. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

11.3 Hum or Buzz Noise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

12 DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

13 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

14 WARRANTY POLICY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

15 SCHEMATICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Caution:

This power amplifier can produce dangerous output
voltage levels, high power levels, and high sound pressure
levels in loudspeakers. In order to minimize the risk of
injury, damage, or hearing loss, please read the entire
owner's manual before connecting to a sound system.

WARNING:

THIS APPARATUS MUST BE EARTHED

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

1. INTRODUCTION

The Ashly FTX Series III MOSFET amplifiers
combine the sonic excellence of a high-end stereo amp
with the ruggedness and stamina necessary in pro audio.
The FTX Series III amps use lateral power MOSFETs
(metal-oxide-semiconductor, field-effect transistors) for
their superior audio fidelity and unmatched reliability as
proven in Ashly amps for over fifteen years. These
MOSFET output devices exhibit many superior perfor­mance characteristics over the conventional bipolar power
transistors used in most conventional power amp designs.
They are inherently self-regulating and do not exhibit
many of the failure modes of bipolar transistors.

MOSFETS have no thermal runaway tendency so
the need for temperature tracking bias circuitry is elimi­nated, making the design simpler and more reliable.

MOSFETS do not suffer from secondary break­down (the primary failure mechanism in in bipolar tran­sistors which requires complex dissipation limiting to
avoid.) The MOSFET will even withstand a shorted load
and self-limit the resulting high drain current without any
protection circuitry for a short time.

MOSFETS do not have a “minority carrier stor­age time” (a phenomenon found in bipolar transistors in
which a certain amount of time is required to turn the
transistor off). Therefore the MOSFET is said to be a
“fast” device which can function very accurately and ef­ficiently with high amplitude/high frequency signals and
transient waveforms.

The FTX series III amplifiers are the result of
years of refinement to the original Ashly MOSFET de­sign. The current circuit is cleaner, quieter, and more
stable than ever before. A number of improvements have
been made in the area of thermal management using new
insulating materials and increased heatsink area, allow­ing even more robust performance into difficult loads.
Protective systems have been refined to add even more
insurance against gross faults such as short circuits and
the application of speaker damaging signals to the ampli­fier. The module assembly is produced using assembly
techniques including individual testing of each compo­nent before it is placed on the PC board, and a state-of­the-art soldering system which insures excellent strength
and ruggedness.

improved power handling, and better matching. The all­metal case of these transistors results in a ruggedness not
possible with plastic designs.

The unmatched reliability of the power MOSFET
output devices, the clever mechanical design, and the
careful assembly techniques of the FTX Series III ampli­fiers ensure years of maintenance-free service.

2. UNPACKING

As a part of our system of quality control, every
Ashly product is carefully inspected before leaving the
factory to ensure flawless appearance. After unpacking,
please inspect for any physical damage. Save the ship­ping carton and all packing materials, as they were care­fully designed to reduce to minimum the possibility of
transportation damage should the unit again require pack­ing and shipping. In the event that damage has occurred,
immediately notify your dealer so that a written claim to
cover the damages can be initiated.

The right to any claim against a public carrier
can be forfeited if the carrier is not notified promptly and
if the shipping carton and packing materials are not avail­able for inspection by the carrier. Save all packing mate­rials until the claim has been settled.

3. AC POWER REQUIREMENTS

3.1 Voltage Requirements

Your FTX Series III amplifier is supplied with a
three conductor grounded AC power cord, and should be
plugged into a standard 3-wire grounded electrical outlet
which supplies 120VAC 50-60 Hz (some export models
are wired for 100 or 240 volts and are labeled as such).
In the event of line voltage sag, or “brown-out”, FTX
Series III amplifiers will continue to operate normally,
albeit with less power.

3.2 Current Requirements

A 15 amp circuit is sufficient for normal opera­tion down to 2Ω loads. The actual AC current consump­tion by the amplifier depends greatly on the audio signal
and the load impedance. For typical audio program ma­terial with the amplifier driving both channels just peak­ing at the clipping level, the following AC line current
capacities are recommended for system design purposes:

The FTX series III uses the latest generation of
lateral MOSFETS. These components also improve on a
time honored design. The result is higher bandwidth,

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

FTX-1001 FTX-1501 FTX-2001

Idle .5A .6A 1.5A
8Ω loads 2 Amps 2.5 Amps 3.5 Amps
4Ω loads 3 Amps 4 Amps 6 Amps
2Ω loads --- 7 Amps 10 Amps

Table 3.1: Recommended AC line current capacity

All FTX Series III amplifiers consume less than

12 amps when operating at 1/8 power into 2Ω loads. This

condition satisfies the UL, CSA and building electrical

code requirements for a piece of audio equipment not to

consume more than 80% of the current available when

plugged into a grounded 15 amp outlet and operated

at 1/

8 of maximum power.

3.3 AC Grounding Requirements

To reduce the risk of ground loop hum, all sys­tem ground references should originate at the same point
in your AC power distribution. Never remove the
amplifier’s ground pin as it is both unlawful and danger­ous, creating a potential shock hazard.

Since power at the speaker load is a primary con­cern in system design, we have included a table to best
determine appropriate wire gauge for your application.
Table 4.1 lists the percentage of the speaker load power
which would be lost in an arbitrary 100 ft run of 2-con­ductor cable. This table expresses the power loss as a
percentage of the load’s power rather than the total am­plifier output power, so that you can use this table to ac­curately determine power loss to the load at other cable
lengths. For example, if you plan to deliver 100 watts to
an 8Ω load through 50 ft of 14 ga. cable, the power loss
in the cable would be 3.2% ÷ 2 = 1.6% of 100 watts or

1.6 watts lost in the cable. Table 4.1 also gives the resis­tance per 100 feet of common copper wire gauges.

Wire Gauge Ω/100ft 8Ω load 4Ω load 2Ω load

#8 .0605Ω 0.8% 1.5% 3.0%

#10 .1018Ω 1.3% 2.5% 5.1%

#12 .1619Ω 2.0% 4.0% 8.1%

#14 .2575Ω 3.2% 6.4% 12.9%

#16 .4094Ω 5.1% 10.2% 20.5%

#18 .6510Ω 8.1% 16.3% 32.6%

Table 4.1: Percentage of speaker load power lost in 100
foot run of 2-conductor cable.

4. CABLE REQUIREMENTS

4.1 Input Cables

Be sure to use shielded cable whether balanced
or unbalanced. Shielding which is properly grounded will
protect the signal from outside electrical interference such
as RF, fluorescent lighting, even computer noise. As a
general rule, unbalanced or single-ended (tip-sleeve) lines
of less than 10 feet are satisfactory, but greater distances
may require a balanced signal. Avoid running input lines
in close proximity or parallel to long speaker lines, AC
power cables, or power transformers, as this may gener­ate hum or oscillation.

4.2 Output Cables

The FTX Series III amplifiers are capable of de­livering high levels of output current, therefore the wire
gauge used for speaker cables is particularly important.
Inadequate wire gauge adds significant resistance to the
speaker’s own impedance, reducing the power which is
actually delivered to the speaker. It will also result in a
decrease in the damping factor and possible fire hazard.

5. RACK-MOUNTING REQUIREMENTS

5.1 Mechanical

All Ashly amps are designed to fit in standard
19-inch racks. The front panel rack-mount ears are suffi­ciently strong for most applications. If you desire further
integrity for mobile racks, we recommend using the four
additional holes in the back of the chassis for supplemen­tal rear-mounting (see dimensional drawings).

5.2 Cooling

If using an FTX amplifier, be certain that both
the front and back of the rack have unhindered access to
free air flow. Fan direction is from front to back. It is
not necessary to leave empty space above or below the
FTX amplifiers, however the CFT-1800 will cool more
efficiently with space above and below the chassis.

The following chart indicates max BTU per hour
for each amp under varying load conditions, so that ac­curate assessment of room ventilation needs can be made.
Thermal output is approximated by subtracting audio
output power from the total power consumption of the
amplifier. All values assume the amplifier is driving both
channels and just peaking at the clipping level.

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

t

AC Power

Off On

FTX-1001 FTX-1501 FTX-2001

Channel One

Channel Two

6. FRONT PANEL FEATURES

-

-

-1-18-21-24-27

-1-18-21-24-27

Outpu

Idle 210 BTU 250 BTU 620 BTU
8Ω loads 550 BTU 580 BTU 760 BTU
4Ω loads 800 BTU 970 BTU 1340 BTU
2Ω loads --- 2030 BTU 2590 BTU

Table 5.2: Max BTU per hour (both channels driven)

5.3 Grounding

In some installations where the sound system is
sensitive to RF noise or system-induced oscillation, it may
be necessary to ground the amplifier's chassis to the rack
enclosure. This is accomplished using star type
lockwashers on the four rack mounting screws. These
star washers will penetrate through the amplifier's paint
to adequately ground the chassis to the rack.

6

6.1 Power Switch

When the unit is switched on there is a 2 second
delay, during which time the PROTECT circuit will acti­vate. The load is disconnected during this power-up se­quence . When turning off the amplifier, the load is re­moved instantly, and the protect LED will briefly turn on
as the power supply discharges.

6.2 Thermal Status Meters

This left-most green LED, when turned on, indi­cates normal thermal status. If either amplifier channel
overheats, these lights will both turn off, indicating that
power has been cut off from the audio portion of the am­plifier. The AC Power Switch will remain lit, and the
cooling fan continues to operate until the amplifier is
within safe operating temperatures again.

Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

v

FTX SERIES III

el

Protect

Protect

-3-6-9

Clip-3-6-9

Clip

6.3 Output Meters

Output meters display peak output voltage in dB,
referenced to full output. For example, if full output in a
given configuration was 400 watts, then “0” would mean
the amp is delivering the full 400 watts to the load, “-6”
would mean the output voltage is 6dB lower, or 100W.

Stere o MOSFET P ow er Amplifier

TX-2001

F

Turn-on delay/Instant turn off

DC voltage at the output (signals below 8 hertz
will be interpreted as DC voltage, and may trig­ger the protect circuit)

6.4 Clipping Indicator

Clipping occurs when the signal peak levels ex­tend beyond the available power supply rails, essentially
“cutting off” the crest portion of the waveform. This pro­duces signal distortion and can potentially damage driv­ers, as the signal begins to look like a square wave. The
red CLIP LED illuminates at the onset of clipping.

6.5 Protect Indicator

Protect mode in ASHLY amplifiers is automati­cally activated during extreme fault conditions, as well
as during power-up and power-down. When in protect
mode, as indicated by the red LED, the speaker output
terminals are internally disconnected. Conditions caus­ing the amplifier to switch into protect mode include the
following:

Output short circuit

Ultrasonic signals at high amplitude

After the abnormal condition ceases, the ampli­fier will automatically recover from protect
mode.

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

7. REAR PANEL FEATURES

7.1 Inputs

The standard input panel of the FTX Series III

amps is equipped with balanced 1/4" tip-ring-sleeve (TRS)
phone jacks, balanced XLR jacks, and balanced screw­terminal inputs. The three types of connectors are inter­nally wired in parallel and may be used with balanced or
unbalanced connections. The inputs are configured for
pin 2 hot, meaning that a positive voltage applied to pin
2 will result in a positive output voltage across the speaker
terminals. Pin 2 of the XLR jack is equivalent to the tip
of the 1/4" TRS jack. A n optional input transformer is
available on all FTX and CFT amplifiers.

Balanced Inputs

It is recommended that balanced input connec­tions be used whenever possible to reduce ground-loop
and environment-induced hum and noise. The (+) signal
is on pin 2 of the XLR, and the tip of the phone jack. The
(-) signal is on pin 3 of the XLR, and the ring of the phone
jack.

Unbalanced Inputs

If an unbalanced input connection is used, then
the (-) connection (XLR pin 3) should be connected to
input ground ( XLR pin 1). If the 1/4" input jack is used
unbalanced, the use of a mono (tip-sleeve) plug will au­tomatically tie the (-) connection to input ground. Never
float pin 2 or pin 3 when using an unbalanced signal.

Figure 7.1: Balanced Input Connections Figure 7.1a: Unbalanced Input Connections

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

Input Ground

The CHASSIS GROUND terminal is internally
connected to the chassis, the AC earth ground, and the
power amplifier’s signal ground. The INPUT GROUND
terminal is tied to the XLR pin 1 and the 1/4" jack sleeve.
It is recommended that the input and chassis ground ter­minals remain connected with the factory-supplied jumper
strap.

In situations where the power amp and its signal
source are separated by great distances, a ground voltage
difference may exist between the amp’s chassis ground
and the input cable’s ground. Connection of these two
grounds through the jumper strap may cause large ground
currents to flow (which is known as a ground loop), caus­ing a hum noise in the amp’s output. Unless you have
such a situation with a hum problem that cannot be solved
by using balanced input connections, the ground jumper
strap should remain in place.

7.2 Normal/Bridging Switch

This switch selects between NORMAL mode in
the “out” position where both channels are in-phase, and
BRIDGING mode in the “in” position where channel 1
input is used to drive both channels, inverting the phase
of channel 2. In BRIDGING mode, the channel 1 red
binding post is the (+) in- phase speaker output terminal
and the channel 2 red binding post becomes the (-) out­of-phase speaker terminal. It is not necessary to depress
the MONO switch in order to operate in BRIDGED mode.
The BRIDGING switch overrides either setting of the
Stereo/Mono Switch.

7.3 Stereo/Parallel Mono Switch

This switch selects between STEREO mode in
the “out” position and PARALLEL MONO mode in the
“in” position. In PARALLEL MONO mode, channel 1
and channel 2 inputs are internally tied together before
the input attenuator, allowing discrete channel control of
a mono signal. CAUTION: Be sure not to have two sig­nal sources connected to ch.1 and ch.2 inputs when in
parallel mono mode, as it would short-circuit these two
signals and result in no output.

7.4 Level Controls

The level controls allow attenuation (calibrated
in dB) of the input signal. In PARALLEL MONO mode,
channel 1 and channel 2 inputs are tied together, while
still preserving independent level control per channel. In
BRIDGED mode, use only channel 1 level control. It is
recommended that the level controls be operated at full
level (0 dB attenuation) in most situations to maximize
the headroom in the signal source.

7.5 Speaker Outputs - Binding Posts

A pair of dual banana binding posts provide the
stereo speaker outputs. In BRIDGING mode, the channel
1 red binding post is the (+) in-phase speaker output ter­minal and the channel 2 red binding post becomes the (-)
out-of-phase speaker terminal.

CAUTION! NEVER CONNECT THE TWO RED
BINDING POSTS TOGETHER OR CONNECT
EITHER RED BINDING POST TO A BLACK
BINDING POST!

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

+15

+6

+3

Limiter

In/Out

-1

-3

Ch.2

Limiter

Threshold

(dB)

0

-3

5

4

3

2

1

0

Level

Low

Level

10

dB

0

-6 -9

Input
Level

+15

+6

+3

Chassis

Ground

Ch.1

Limiter

Threshold

(dB)

0

-3

(+)

Norm

Bridge

(-)

Input

Ground

PUSH

PUSH

Stereo

Mono

Limit Limit

-28+18

-12

-9

-6

6

9

10

Channel 2

Output

0

5

-

∞∞

-21

-15

Modes

123

Ch.2 Ch.1

1.Low High (FR)

2.Low Low

3.Bridged Low
Ch.2 is (+)

PUSH

PUSH

Balanced Input

(Pin 2 Hot)

High (FR)

Level

10 0

5

Highpass

Full Range
CAUTION: Never Send Full Range
Signal To High Fr eque ncy Drivers.

(-)

(+)

Input

Ground

Chassis

Ground

-28+18

-12

-9

-6

(-)

(+)

Phase

+180 0

+360 +180

CL-2

POWERCARD

Input Option

Stereo Limiter

PUSH

PUSH

Channel 1 (Mono)

CD

Horn EQ

1.2KHz

2.4KHz

Off

POWERCARD I nput Option

Two-W ay 24dB/Oct.

Aux

Low Ou t

(Pre Level)

5

4

6

1

010

Level

Installed

Crossover

Frequency:

XR-1

Crossover

Aux

High Out

(Pre Level)

7

8

9

Limiter
In/Out

Figure 8.2: CL-2
Peak Limiter ­Compressor

Figure 8.3: XR-1
Two-Way
Crossover

Phan.

(+15V)

10

Microphone Inputs (Mono)

-1- -2-

PUSH

PUSH

10

0

100

Ch.1 Ch.2 Ch.3 Ch.4

PUSH

PUSH

0

Line Level

L = Amp l ifier C h a nn el 1 Outp ut
R = Amp l ifie r C h a nn e l 2 Ou tpu t
Mono Mode Sums the Stereo Signals

10010

10

Mic 1

Level

1

2

0

10

0

Mic 2

Level

L

R

Line Inputs

Low-Cut

(Mic s O n l y)

3

4

Master

Level

5

4

3

2

1

0

L

R

Insert Points

(Post Ma ste r Le vel)

6

7

9

10

Send

Return

Stere o

Mono

8

MM-6

POWERCARD

Input Option

Mic/Line Mixer

Norm

Bridge

Figure 8.4: MM-6
Mic - Line Mixer

Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

8. INPUT OPTIONS

Input option panels are available to provide built-in features
such as a stereo compressor-limiter, a mic and line mixer, a crossover
for bi-amplified systems, and input transformers for signal isolation.
In addition to the FTX amplifiers, input options can be installed on
MFA High-Power amps, the CFT-1800 convection cooled amp, and P70
series 70 volt amps. A brief description of currently stocked input op­tions follows. Consult your dealer for detailed information on input
options, or call the factory at 800-828-6308.

8.1 Input Isolation Transformer (not shown)

The input transformer provides complete electrical isolation
from the amplifier and its signal source to eliminate any ground-in­duced hum noise. The transformer input also further reduces any com­mon-mode noise and radio frequency interference. The transformer
option is factory installed in a standard input panel and does not change
the operation of any switches or controls.

8.2 Peak Limiter/Compressor

The limiter input option provides peak signal limiting from
excessive input levels for speaker protection and overall level control.
Separate limiter threshold controls, limit indicator LED’s and limit on/
off switches are provided on each channel allowing fully discrete ste­reo limiting operation.

8.3 Two-Way Crossover

The crossover input option provides fixed-frequency 24 dB/
octave high-pass and low pass filters allowing the two amplifier chan­nels to operate bi-amped, full range with low out, both channels low
out, or bridged low out. Auxiliary low and high outputs are available
for connecting additional amplifiers. Included with the crossover in­put option are single in-line package (SIP) resistor networks which al­low preselection between standard crossover frequencies of 160Hz,
500Hz, 750Hz, 1.2KHz, and 1.6KHz. 360° of phase control is pro­vided for proper acoustical alignment of high and low frequency driv­ers. Selectable constant directivity horn EQ is provided for both small
and large horn designs.

8.4 Six Input Mic-Line Mixer

The mixer input option provides four high-impedance line in­puts and two balanced low-impedance microphone inputs, each with its
own level control. A switchable 200 Hz high-pass filter is provided on
the mic inputs to reduce unwanted low frequency noise. An internal
jumper allows selection of 15 Volt phantom power applied to the mic
inputs for use with condenser mics. The option has a master level con­trol and selectable stereo, mono and bridging modes. Insert Points are
available for patching external processing into the left and right chan­nels.

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9. TYPICAL APPLICATIONS

9.1 Stereo Operation

(Both switches out, both inputs used, both level controls used, both outputs used)

9.2 Parallel Mono Operation

(Parallel mono switch in, channel 1 input used, both level controls used, both outputs used)

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

9.3 Bridged Mono Operation

(Normal/bridging switch in, channel 1 input used, channel 1 level control used, BRIDGED output used)

10. DESIGN THEORY

Ashly FTX Series III amplifier circuits are totally
discrete using high-voltage, wide bandwidth electronics.
The input section is a complimentary Darlington differen­tial amplifier stage for high common-mode rejection, low
noise and low distortion. All voltage gain stages in the
amplifier operate class A for low distortion. The compli­mentary MOSFET output stage has almost infinite cur­rent gain, therefore the output driver stages are nearly
lossless. All circuitry within the feedback loop is discrete
which allows the amplifier to recover instantly and cleanly
without any spikes or glitches from a clipped condition.
This overall design approach inherently assures low noise,
low distortion, and excellent transient and overload re­sponse. Inputs are bridging and active balanced, and all
input connections can operate as balanced or unbalanced.
The MOSFET output devices themselves do not require
short circuit protection and V.I. limiting circuitry; how­ever, output relays are employed for turn-on delay and
speaker protection from fault conditions. The output re­lays will open if DC voltage, ultrasonic signals, a shorted
output, or an internal amplifier failure is detected. Any of
these fault conditions will illuminate the protect mode
LEDs on the front panel. Each amplifier channel operates
completely independent of the other so that one channel
in protect mode will not affect the other channel. Designed

into the FTX Series III and CFT amplifiers is the hard­ware necessary for computer control and monitoring as
such systems become available. All electronic components
are mounted to rugged plated-through glass-epoxy circuit
boards. Large computer-grade electrolytic capacitors as­sure long service.

The FTX Series III amplifiers are packaged in a
rugged 16-gauge steel chasses. The power transformer is
located at the front center of the chassis to minimize front
panel torsion. Each channel’s electronics and heat sink
are identical yet completely independent and modular,
each with a single plug-in connector for ease of servic­ing. Large custom black-anodized extruded aluminum
heat sinks with fan cooling provide plenty of thermal head­room.

The CFT-1800 utilizes quiet convection cooling
for studio control rooms, home hi-fi, and other applica­tions where low ambient noise is essential. Like the FTX
Series III, the CFT-1800 is a modular design for ease of
servicing. Because of the passive cooling in the CFT­1800, thermal headroom is somewhat reduced from that
of forced air cooling, thus making it inadvisable to drive
4 ohm loads at continuous high power with this ampli­fier. It is also important to allow for free air circulation
above and below the amplifier to achieve optimum cool­ing action.

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11. TROUBLESHOOTING TIPS

11.1 No Audio Output

Power switch not lit:

Line fuse is blown or power outlet is dead.

IF LINE FUSE IS BLOWN, REPLACE ONLY
WITH SAME TYPE AND RATING FUSE.

Power switch is lit but thermal status LEDs are off:

Amp is in thermal protect mode. Power has been
removed fr om the audio section until the amplifier
returns to a normal temperature.

Power and Thermal Status are lit but Output Level Meters
are not responding:

There is no input signal applied or input level
controls are off. Note: In parallel mono mode,
be sure that only one signal source is connected
to the amp.

Protect LED is lit and relay clicking is heard:

11.2 Distorted Sound

Output level meters indicate 0dB level (red CLIP LED on):

Amplifier is being clipped. Reduce the signal
level at the signal source.

0 dB level on output meters is never reached:

Applied input signal is distorted before it gets to
the amp. Check to see if a piece of equipment in
the signal chain before the amp is clipping.
Normally the amplifier should be operated with
input levels fully CW to maximize headroom in
the signal source. Also check for damaged
speaker drivers that could cause distorted sound.

If distorted sound is still heard, there may be an

internal problem. Call Ashly Audio service department at
800-828-6308.

11.3 Hum or Buzz Noise

Be sure that the power cord’s 3-prong plug is con-

nected to a properly earth-grounded outlet. Lifting the
grounding third prong usually does not improve hum or
buzz and creates a potential electrical shock hazard.

Output is short circuited or load impedance is
too low . Check speaker cables for shorts, incr ease
load impedance by disconnecting some speakers.

A high frequency oscillation in the sound system
is occuring when the relays close. Turn down
the input level controls to verify that the amplifier
alone is not causing the problem.

Be sure to use good quality shielded and balanced
input cables. Do not run input cables alongside
output speaker wires over long lengths (ie.
through the same conduit).

Protect LED is lit, Clip LED comes on as soon as signal
is applied:

DC voltage may be present on the output or an
internal slow acting protection fuse may have
blown. Have a qualified technician replace the
fuse with the same type fuse.

Use balanced input connections with a balanced

audio source for best hum and buzz rejection. See sec­tion 7.1 on inputs.

Normally the ground lift strap on the input screw

terminals should be left in place for best ground voltage
suppression. In some cases hum or buzz noise may be
induced by excessive ground current through the input
ground connection. This current path may be interrupted
by removing the ground lift strap. If the problem per­sists, input signal transformers providing complete ground
isolation are available. See section 8.1 on Input Isola­tion Transformer.

Buzz noise can be caused by lighting dimmers or

neon lights. Try moving the amplifier, wiring, or light­ing to different location to see if lighting is the source of
the buzz. Input transformers may also fix the problem.
See section 8.1 on Input Isolation Transformer.

12. DIMENSIONS

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13. SPECIFICATIONS

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

20KW balanced

13.1 Output Power

13.10 Bandwidth

Maximum Average Power, 0.1% THD, 1KHz

RMS Watts Per Channel, Both Channels Driven

13.11 Slew Rate

FTX-1001 FTX-1501 FTX-2001

100KHz

50V/µS

8 ohms: 120W 200W 300W
4 ohms: 175W 300W 500W
2 ohms: --- 380W 675W

Bridged Mono Mode:

8 ohms: 350W 600W 1000W
4 ohms: --- 760W 1350W

FTC Continuous Power, 0.1% THD, 20Hz-20KHz

RMS Watts Per Channel, Both Channels Driven

8 ohms: 120W 190W 290W
4 ohms: 170W 280W 475W

Bridged Mono Mode:

8 ohms: 340W 560W 950W

13.2 Frequency Response:

±0.2dB 20Hz - 20KHz

13.3 Total Harmonic Distortion:

.007% 1ΚΗz, 8Ω
.01% 20Hz 8Ω
.05% 20Hz-20KHz 8Ω

13.4 IM Distortion

(SMPTE): .007% 8W
(IHF): .01% 8W

13.12 Rise Time

2µS 10%-90%

13.13 Power Requirements

110-125VAC, 50-60Hz (240V Available)

13.14 Shipping Weight:

41 lbs. 46lbs. 60lbs.

Specification conditions are 120VAC 60Hz at 25°C.

14. WARRANTY POLICY

We thank you for your expression of confidence

in Ashly products. The unit you have just purchased is
protected by a limited five year warranty. To establish
the warranty, you must first complete and mail the war­ranty card attached to your product.

Fill out the information below for your records.

Model Number _________________________________
Serial Number _________________________________
Dealer ________________________________________
Date of Purchase _______________________________
Dealer’s Address _______________________________

13.5 Output Hum And Noise:

(dB below full output 20Hz - 20KHz, unweighted)

>100dB >100dB >105dB

13.6 Damping Factor:

>250 into 8Ω, <1KHz

13.7 Full Power Input Sensitivity:

1 Vrms 1.3Vrms 1.7Vrms

13.8 Voltage Gain:

28´ = 29dB

13.9 Input Impedance:

16

_______________________________________________

_______________________________________________
Dealer’s Phone _________________________________
Salesperson ____________________________________

OTHER INFORMATION:
_______________________________________________

_______________________________________________

_______________________________________________

15. SCHEMATICS

Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

Figure 15.1: FTX 2001 Block Diagram

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

Figure 15.2: FTX Power Amplifier Module

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

Figure 15.3: FTX Power Amplifier Standard Input and Meter

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

ASHLY AUDIO INC. 847 Holt Road Webster, NY 14580-9103

Phone: [phone] Fax: [phone]

Toll Free [phone] Internet: http://www.ashly.com/

 1998 by Ashly Audio Corporation. All rights reser ved worldwide.

Printed in USA 1/98 FTX Rev 7